Speckle reduction of SAR images in the complex wavelet domain

Dual tree complex wavelet transformation (CWT), proposed by N. G. Kingsbury (1999), is used for speckle reduction of SAR images. The CWT is useful for speckle reduction through its subband images and the speckle reduction is obtained by thresholding the subband-image coefficients of the digitized SAR images. Two thresholding methods are used; soft thresholding and thresholding using non-linear functions which are adapted for each of selected subband and is based on sigmiod functions. The denoising method shows great promise for speckle removal and hence should provide good detection performance for SAR based recognition.